In Roundcube Webmail before 1.6.18 and 1.7.x before 1.7.3, the modoboa driver of the password plugin could leak a Modoboa API authentication token to a user-controlled host via crafted session data. This issue only affects Roundcube instances using the password plugin with its modoboa driver.
In Roundcube Webmail before 1.6.18 and 1.7.x before 1.7.3, the LDAP search filter was subject to injection via unescaped %u/%fu/%d substitution, which may lead to information disclosure or privilege escalation.
In Roundcube Webmail before 1.6.18 and 1.7.x before 1.7.3, insufficient Cascading Style Sheets (CSS) sanitization in HTML e-mail messages may lead to SSRF or Information Disclosure, e.g., if stylesheet links point to local network hosts. This issue exists because of insufficient fixes for CVE-2026-35540, CVE-2026-48843 and CVE-2026-62643.
In Roundcube Webmail before 1.6.18 and 1.7.x before 1.7.3, improper rule name quoting could lead to managesievedisabledactions setting bypass via a crafted rule name in a Sieve script. This issue only affects Roundcube instances using the managesieve plugin.
In Roundcube Webmail before 1.6.18 and 1.7.x before 1.7.3, an unclosed url() in a FuncIRI attribute of an SVG image could evade the remote image blocking, which may lead to information disclosure or privilege escalation.
In Roundcube Webmail before 1.6.18 and 1.7.x before 1.7.3, mail search and LITERAL+ byte-count desynchronization could lead to information disclosure or privilege escalation via IMAP command injection.
In Roundcube Webmail before 1.6.18 and 1.7.x before 1.7.3, improper HTML/CSS sanitization of the SVG animate "by" attribute may lead to remote image blocking bypass, which in turn may lead to information disclosure or privilege escalation.
In Roundcube Webmail before 1.6.18 and 1.7.x before 1.7.3, the "Add to address book" action was subject to stored XSS.
In Roundcube Webmail before 1.6.18 and 1.7.x before 1.7.3, responses from the CSS (Cascading Style Sheets) proxy were not validated, which may result in information disclosure or XSS (cross-site scripting) via MIME sniffing.
In Roundcube Webmail before 1.6.18 and 1.7.x before 1.7.3, the cmdlearn driver of the markasjunk plugin is subject to remote code execution via crafted placeholder replacement values. This issue only affects Roundcube instances using the markasjunk plugin with its cmdlearn driver.
In Roundcube Webmail before 1.6.17 and 1.7.x before 1.7.2, there is Stored Cross-Site Scripting (XSS) via a crafted plain-text email message. The attacker-controlled JavaScript executes within the victim's authenticated session simply by opening or previewing the message (zero-click).
In Roundcube Webmail before 1.6.17 and 1.7.x before 1.7.2, the password plugin of the Roundcube Webmail was subject to username spoofing via session data, which could lead to account takeover.
In Roundcube Webmail before 1.6.17 and 1.7.x before 1.7.2, insufficient Cascading Style Sheets (CSS) sanitization in HTML e-mail messages may lead to SSRF or Information Disclosure, e.g., if stylesheet links point to local network hosts. NOTE: this issue exists because of insufficient fixes for CVE-2026-35540 and CVE-2026-48843.
In Roundcube Webmail before 1.6.17 and 1.7.x before 1.7.2, an infinite loop was discovered in the TNEF decoder, which may lead to denial of service upon opening an email with a TNEF attachment.
In Roundcube Webmail before 1.6.17 and 1.7.x before 1.7.2, the TNEF decoder was subject to denial of service via a crafted compressed-RTF size.
An issue was discovered in Roundcube Webmail before 1.5.15 and 1.6.15. The remote image blocking feature can be bypassed via SVG content in an e-mail message. This may lead to information disclosure or access-control bypass. This involves the animate element with attributeName=fill/filter/stroke.
An issue was discovered in Roundcube Webmail before 1.5.14 and 1.6.14. Insufficient Cascading Style Sheets (CSS) sanitization in HTML e-mail messages may lead to a fixed-position mitigation bypass via the use of !important.
An issue was discovered in Roundcube Webmail before 1.5.14 and 1.6.14. The remote image blocking feature can be bypassed via SVG content (with animate attributes) in an e-mail message. This may lead to information disclosure or access-control bypass.
An issue was discovered in Roundcube Webmail before 1.5.14 and 1.6.14. The remote image blocking feature can be bypassed via a crafted background attribute of a BODY element in an e-mail message. This may lead to information disclosure or access-control bypass.
An issue was discovered in Roundcube Webmail before 1.5.14 and 1.6.14. Incorrect password comparison in the password plugin could lead to type confusion that allows a password change without knowing the old password.
An issue was discovered in Roundcube Webmail 1.6.0 before 1.6.14. Insufficient Cascading Style Sheets (CSS) sanitization in HTML e-mail messages may lead to SSRF or Information Disclosure, e.g., if stylesheet links point to local network hosts.
An issue was discovered in Roundcube Webmail before 1.5.14 and 1.6.14. XSS exists because of insufficient HTML attachment sanitization in preview mode. A victim must preview a text/html attachment.
An issue was discovered in Roundcube Webmail before 1.5.14 and 1.6.14. Unsanitized IMAP SEARCH command arguments could lead to IMAP injection or CSRF bypass during mail search.
An issue was discovered in Roundcube Webmail before 1.5.14 and 1.6.14. Unsafe deserialization in the redis/memcache session handler may lead to arbitrary file write operations by unauthenticated attackers via crafted session data.
Last updated 30 June 2026
Roundcube Webmail before 1.5.12 and 1.6 before 1.6.12 is prone to a information disclosure vulnerability in the HTML style sanitizer.
Hi,
Roundcube just published an update that appears to contain an important security fix: https://roundcube.net/news/2025/06/01/security-updates-1.6.11-and-1.5.10
"Fix Post-Auth RCE via PHP Object Deserialization reported by firs0v."
Even though it says "Post-Auth", impact is likely high, as for a webmailer, it is a very common scenario that many people are potentially authenticated. (And it may just be another XSS away from non-authenticated RCE.)
-- Hanno Böck - Independent security researcher https://itsec.hboeck.de/ https://badkeys.info/
Roundcube Webmail before 1.5.10 and 1.6.x before 1.6.11 allows remote code execution by authenticated users because the from parameter in a URL is not validated in program/actions/settings/upload.php, leading to PHP Object Deserialization.
Cross-Site Scripting (XSS) vulnerability in Roundcube Webmail 1.6.9 allows remote authenticated users to upload a malicious file as an email attachment, leading to the triggering of the XSS by visiting the SENT session.